So she doesn't want to do it, and has two choices. If she decides to do it to try and make you happy, you punish her by taking away the very thing she was trying to obtain - intimacy. So instead, she decides not to do it. Well, guess what? You expressed that it's something you wanted, so over time you'll get increasingly resentful that she's not returning the favor. So what starts off as an initial victory becomes more and more of an issue over time. She loses, again.
The only way for her to win is to want to do it, but guess what? She can't really control that. She can only want to make you happy, and be willing to try it out as a means to accomplish it. But of course, that's not good enough.
She loses no matter what.